
Prune suckers all summer long to keep the plant healthy. This method also leaves a few inches on the sucker to reduce the shock to the plant. This technique is better when you’re dealing with large suckers if the wound becomes diseased, it will be further away from the main stem. The drawback is that suckers will develop from the stem that you leave behind, which will require additional pruning.
If it’s thicker than a pencil, use the “Missouri pruning” method and pinch out just the tip of the sucker, leaving one or two leaves behind for photosynthesis and to protect developing fruit from sun scald. Thicker suckers should not be snapped off, since this could damage the whole plant.
By improving ventilation, you’re helping to protect the plant. Humidity can make it easier for sicknesses to flourish, and it also causes the wounds that are created while pruning to dry up more slowly making the plant longer vulnerable. On the other hand, if your plant is in a humid environment (such as a greenhouse), remove everything below the first flower cluster to improve ventilation. They are important for helping to shade the ground until the plant matures.
As for stems and leaves, not the suckers, growing below the first flower cluster: If you live in a warmer zone such as Zone 9, you should leave them on until they turn yellow. This should ideally be done when the shoot is young and supple. To remove a sucker, grab a growing tip by the base between the thumb and forefinger and bend it back and forth until it snaps cleanly.